Investigation on time-dependent behaviour and long-term stability of underground water-sealed cavern

Abstract

With the help of an automatic servo-controlled triaxial rock creep system, typical whole process rheological curve is obtained through laboratory experiment on the surrounding diorite rock of a large underground water-sealed cavern project. Creep experiments show that diorite exhibits obvious creep behaviour under the high in situ stress. Based on the experiment results, this article studies the creep behaviour under different stress levels, analyses the creep failure mode and mechanism, and obtains the triaxial creep properties of diorite. Using a three-dimensional nonlinear numerical method and the modified hydro-mechanical coupled Cvisc creep model, creep behaviour of the surrounding rock during the long-term operation is simulated and time-dependent stability is analysed. The results indicate that creep deformation is evident, and local stress concentration is relieved due to stress redistribution. After a period of time, the creep rate becomes stable and the deformation is stabilised. Because of its theoretical and practical significance, hydro-mechanical coupled creep analysis is important for the long-term stability and safety evaluation.

Keywords:

• rock mechanics
• triaxial creep experiment
• hydro-mechanical coupling
• underground water-sealed cavern
• long-term stability

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported financially by the Qing Lan Project; National Basic Research Program of China (973 Program) [grant number 2011CB013504]; the National Natural Science Foundation of China [grant number 11172090], [grant number 51479049], [grant number 51209075], [grant number 11272113].